Method for fabricating core substrate using paste bumps

Abstract

A core substrate and multilayer printed circuit board using paste bumps and manufacturing method thereof are disclosed. With the method of manufacturing a core substrate using paste bumps comprising: (a) aligning a pair of paste bump boards, each of which has a plurality of paste bumps joined to its surface, such that the paste bumps face each other, and (b) pressing the pair of paste bump boards together, where an insulation element is placed between the pair of paste bump boards, it is easier to implement interlayer electrical interconnection between circuit patterns, the thickness of the core substrate can readily be adjusted by adjusting the thickness of the insulation layer, the stiffness is improved as a pair of paste bump boards are pressed from the top and bottom, and high-density wiring can be formed more easily as the paste bumps are connected in pairs so that the diameters of the paste bumps formed on the paste bump boards can be reduced.

1. A method for fabricating a core substrate using paste bumps, the method comprising:
 printing the paste bumps on a pair of copper foils; 
 setting the paste bumps; 
 forming a pair of paste bump boards by stacking an insulation element on each of the copper foils such that the paste bumps penetrate the insulation element; 
 aligning the pair of paste bump boards, such that the paste bumps face each other; and 
 pressing the pair of paste bump boards such that the paste bump contact directly together, 
 wherein through holes are formed in the insulation element in correspondence with positions of the plurality of paste bumps. 
 
     
     
       2. The method of  claim 1 , wherein the through-holes are formed by laser drilling or mechanical drilling. 
     
     
       3. The method of  claim 1 , wherein the paste bumps include silver paste. 
     
     
       4. The method of  claim 1 , wherein the paste bumps have a strength greater than that of the insulation element.